Final answer:
When changing lanes, you should signal your intention, look in your mirrors, and check your blind spots.
Step-by-step explanation:
When changing lanes, it is important to follow a few key steps to ensure safety. Firstly, signal your intention to change lanes by using your turn signal. This alerts other drivers of your intention to switch lanes. Secondly, look in your rearview and side mirrors to check for any cars approaching from behind. This helps you gauge if it is safe to change lanes. Lastly, it is crucial to check your blind spots before making your move. Blind spots are areas that are not visible in your mirrors, so it is important to turn your head and physically check these areas to ensure there are no cars in them. Therefore, the correct answer is D. All of the above.